已知離散型隨機變量 X 的概率分布為
X 10 20 30 40
P 0.2 0.1 0.5 a
(1)求常數 a ; (2)求 X 的數學期望 EX .
暫無解析
下述情況出現宮縮乏力時,可用催產素產的是
Mostofusaretaughttopayattentiontowhatissaid—thewords.Wordsdoprovideuswithsomeinformation,butmeaningsarederivedfromsomanyothersourcesthatitwouldhinderoureffectivenessasapartnertoarelationshiptorelytooheavilyonwordsalone.Wordsareusedtodescribeonlyasmallpartofthemanyideasweassociatewithanygivenmessage.Sometimeswecangaininsightintosomeofthoseassociationsifwelistenformorethanwords.Wedon’talwayssaywhatwemeanormeanwhatwesay.Sometimesourwordsdon’tmeananythingexcept“I’mlettingoffsomesteam.Idon’treallywantyoutopaycloseattentiontowhatI’msaying.JustpayattentiontowhatI’mfeeling.”Mostlywemeanseveralthingsatonce.Apersonwantingtopurchaseahousesaystothecurrentowner,“ThisstephastobefixedbeforeI’llbuy.”Theownersays,“It’sbeenlikethatforyears.”Actually,thestephasn’tbeenlikethatforyears,buttheunspokenmessageis:“Idon’twanttofixit.Weputupwithit.Whycan’tyou?”Thesearchforamoreexpansiveviewofmeaningcanbedevelopedofexaminingamessageintermsofwhosaidit,whenitoccurred,therelatedconditionsorsituation,andhowitwassaid.
Whenamessageoccurscanalsorevealassociatedmeaning.Letusassumetwocouplesdoexactlythesameamountofkissingandarguing.Butonecouplealwayskissesafteranargumentandtheothercouplealwaysarguesafterakiss.Theorderingofthebehaviorsmaymeanagreatdealmorethanthefrequencyofthebehavior.Afriend’sunusuallydocilebehaviormayonlybeunderstoodbynotingthatitwasprecededbysituationsthatrequiredanabnormalamountofassertiveness.Someresponsesmaybedirectlylinkedtoadevelopingpatternofresponsesanddefylogic.Forexample,apersonwhosays“No!”toaserialsofchargeslike“You’redumb,”“You’relazy,”and“You’redishonest,”mayalsosay“No!”andtrytojustifyhisorherresponseifthenextstatementis“Andyou’regoodlooking.”
Wewoulddowelltolistenforhowmessagesarepresented.Thewords,“Ifsurehasbeennicetohaveyouover,”canbesaidwithemphasisandexcitementorritualistically.Thephrasecanbesaidonceorrepeatedseveraltimes.Andthemeaningsweassociatewiththephrasewillchangeaccordingly.Sometimesifwesaysomethinginfrequentlyitassumesmoreimportance;sometimesthemorewesaysomethingthelessimportanceitassumes.
1.Effectivecommunicationisrenderedpossiblebetweentwoconversingpartners,if___.
A.theyuseproperwordstocarrytheirideas.
B.theybothspeaktrulyoftheirownfeelings.
C.theytrytounderstandeachother’sideasbeyondwords.
D.theyarecapableofassociatingmeaningwiththeirwords.
2.“I’mlettingoffsomesteam”inparagraph1means___.
A.I’mjustcallingyourattention.
B.I’mjustkidding.
C.I’mjustsayingtheopposite.
D.I’mjustgivingoffsomesound.
3.Thehouse-owner’sexampleshowsthatheactuallymeans___.
A.thestephasbeenlikethatforyears.
B.hedoesn’tthinkitnecessarytofixthestep.
C.theconditionofthestepisonlyaminorfault.
D.thecostinvolvedinthefixingshouldbeshared.
4.Someresponsesandbehaviorsmayappearveryillogical,butarejustifiableif___.
A.linkedtoanabnormalamountofassertiveness.
B.seenasone’shabitualpatternofbehavior.
C.takenaspartofanorderingsequence.
D.expressedtoaseriesofcharges.
5.Theword“ritualistically”inthelastparagraphequalssomethingdone___.
A.withouttrueintention.
B.light-heartedly.
C.inawayofceremony.
D.withlessemphasis.
Passage3
Questions11to15arebasedonthefollowingpassage:
UnliketheirAmericanorEuropeancounterparts,carsalesmeninJapanworkhardtogetabuyer.Insteadoflyinglazilyaroundshowroomswaitingforcustomerstodropby,manyJapanesecarsalesmenstillgoouttogetthem.Theywalkwearilyalongthestreetscarsdoor-to-door.Newcustomersarehuntedwithfruitandcakesontheirbirthdays.Butlifeisgettingtough,andnotjustbecausenew-carsalesarefalling.
WithmoreJapanesewomen(whooftencontrolthehouseholdbudget)goingouttowork,thesalesmenincreasinglyfindnobodyathomewhentheycall.Thatmeansanothervisitintheeveningortheweekend.Thentheyfaceanextraproblem:morepeople,especiallytheyoung,prefertochooseanewcarfromashowroomwheretheycancomparedifferentmodels.
Evenaslateasthemid-1980ssome90%ofnewcarsweresolddoor-to-door.Insomeruralareasmostnewcarsarestillsoldthisway.Butinthebigcitiesmorethanhalfthenewcarsarenowsoldfromshowrooms.
AlthoughinvestinginshowroomsisexpensivebecauseofthehighcostofJapaneseland,dealershavelittlechoice.AlaborshortageandhigheramongJapan’sworkforcearemakingitdifficulttohiredoor-to-doorsalesmen.MostofaJapanesecarsalesman’sworkingdayisspentdoingfavorsforcustomers,likearranginginsuranceorpickingupvehiclesforservicing,ratherthanactuallyselling.
Japan’sdoorstepcarsalesmenarenotabouttovanish.Thepersonalservicetheyprovideissodeep-rootedinJapanthattheyarelikelytooperatealongsidetheglitteringnewshowrooms.Thetwosystemsevencomplementeachother.Whatincreasinglyhappensisthattheshowroomattractstheinterestofapotentialbuyer,givingthefootsoresalesmenafirmleadtofollowupwithahomevisit.
11.Japanesecarsalesusuallydonotwaitatshowroomsforcustomerstodropby;instead,.
A.theysellcarsdoor-to-door
B.theybuypresentsfortheircustomers
C.theyenjoythemselvesinrecreationcenters
D.theygoouttodomarketresearches
12.Impliedbutstated:thecompetitionincarmarketis.
A.lightB.moderateC.fierceD.unfair
13.Youngpeopleliketobuyanewcar.
A.athomeB.fromashowroom
C.madeintheU.S.A.D.madeinJapan
14.ThesquadronofJapanesecarsalesmenisreducingbecauseof.
A.alaborshortage
B.higherexpectationsamongJapan’sworkforce
C.highcostland
D.bothAandB
15.Japanesecarsalesmentotheircustomersmanyfavorssuchas.
A.showingthemaroundinanexhibition
B.arranginginsurance
C.payingthemavisitonweekends
D.sellingolecarsforthem
PartVWriting
Directions:Forthispart,youareallowed30minutestowriteacompositiononthetopic:KeepingFit.Youshouldwriteatleast100—120wordsandyoushouldbaseyourcompositionontheoutline(giveninChinese)below:
1、保持健康的重要性;
2、保持健康的有效途徑;
3、我的做法。
Passage4
Questions16to20arebasedonthefollowingpassage:
Thenewglobalsatellitecommunicationssystemswillofferthreekindsservice,whichmayoverlapinmanydifferentkindsofreceivers.
VOICE.SatellitetelephoneswillbeabletomakecallsfromanywhereontheEarthtoanywhereelse.Thatcouldmakethemespeciallyusefultoremote,thirdworldvillages(someofwhichalreadyusestationarysatellitetelephones),explorersanddisaster-reliefteams.Today’smobiletelephonesdependonearth-boundtransmitters,wheretechnicalstandardsvaryfromcountrytocountry.Sobusinesstravelerscannotusetheirmobilephonesoninternationaltrips.Satellitetelephoneswouldmakethatpossible.
MESSAGING.Satellitemassagershavethesameglobalcoverageassatellitetelephones,butcarrytextalone,whichcouldbeusefulforthosewithlaptopcomputers.Equippedwithasmallscreenliketoday’spapers,satellitemassagerswillalsoreceiveshortmessages.
TRACKING.Voiceandmessagingsystemswillalsotelltheiruserswheretheyaretowithinafewhundredmeters.Combinedwiththemessagingservice,thelocationservicecouldhelprescueteamstofindstrandedadventurers,thepolicetofindstolencars,exporterstofollowtheprogressofcargoes,andhaulagecompaniestocheckthatdriversarenotdetouringthepub.America’smilitaryGlobalPositioningSystem(GPS)satellitewillprovidebetterpositioninginformationtoanyonewhohasareceiverfortheirsignals,butGPSdoesnotcarrymessages,sosuchareceivercannotbeusedonitsownfortrackingorrescue.Bythemid-1990s,GPSreceiverswillbeabletotellpeoplewheretheyaretowithin70metersanywhereintheworld,andtowithinameterorsoinareaswheretheserviceissupplementedbyground-basedtransmitter.
16.Globalsatellitecommunicationssystemswillbeusefulto.
A.laptopcomputerusers
B.remotevillages
C.disaster-reliefteams
D.allabove
17.Satellitetelephonewillmake.
A.businesstravelersusemobilephonesoninternationaltrips
B.possiblecallsfromanywhereonearthtoanywhereelse
C.explorershappy
D.allabove
18.Whichofthefollowingistrue?
A.ThepositioningprecisionofthevoicesystemisbetterthanthatofGPS.
B.ThepositioningprecisionofGPSisBetterthanthatofthevoicesystem.
C.ThepositioningprecisionofthemessagingsystemisbetterthanofGPS.
D.Thepositioningprecisionofvoicesystemisbetterthanthatofthemessagingsystem.
19.Whatcanwesayaboutthenewglobalsatellitecommunicationssystems?
A.Theyarewidelyused.
B.Theyareveryhelpful.
C.Theyarecostly.
D.BothAandB.
20.Whichofthefollowingmaybethebesttitleforthepassage?
A.GlobalSatelliteCommunications
B.NewVoiceandMessagingSystem
C.NewGenerationSatellite
D.AlwaysinTouch